Bimetal strip cleaner



g- 10, 1954 K. E. BOOKE ETAL 2,685,701

BIMETAL STRIP CLEANER Filed March 15, 1952 INVENTORS KENNETH E. BOO/(EJOHN F G/LMORE A TTORNEV Patented Aug. 10,, 1954 UNITED STA'iEfi i hi'i'iifii QFFICE BIMETAL STREP CLEANER Application March 15, 1952,Serial No. 276,862

The present invention relates to the manufacture of glow switches and,more particularly, to the treatment of the bin1etal strip prior tocutting to length and mounting said strip in a glow switch assembly.

The glow type starting switch for a fluorescent lamp consists of twoelectrodes, one of which is a bi-meta1 strip, enclosed in a small glassbulb filled with an inert gas, such as neon or argon. When the voltageis applied, a small current flows through the circuit, as a result of aglow discharge between the two electrodes. The heating effect of thecurrent expands the bi-rnetallic strip ele- 5 Claims. (Cl. -192) mentand causes the electrodes to touch, thereby stopping the glow discharge,but permitting a substantial how of current to preheat the fluorescentlam electrodes.

In the past, the bi-metal strip was originally unreeled and fed directlyinto'a lei-metal strip welding machine, which cut on", formed and weldedthe oi-metallic strip in place low switch assemblies. Often the bi-metalstrip, as received, was dirty, thereby causing defective welds in theglow switch assembly and introducing deleterious material into the glowswitch itself.

Hence, it has been found advantageous according to our invention, toprovide apparatus for Washing and drying the bi-metal completely,

prior to entry into the welding machine. This apparatus washes the stripthoroughly in boiling Water. I his is accomplished without running thelei-metal strip through bends that would deform or give it a permanentset. Washing the bimetal strip in the washer of our invention alsoprevents the creation of a deleterious steam laden atmosphere around thebi-metal welding machine.

The strip washer of our invention consists of a tank contained within adome-shaped condensing hood, both having slitted felt pads at each endportion, a blower mounted on top to condense the steam inside the hoodand dry the emerging washed bi-netal strip, and means for heating thecirculating water in the tank.

In its general aspect, the resent invention has as its objective theelimination of the defects and disadvantages of priorart processing ofbi-metal strip.

A specific object of the invention is the elimination of dirty bi-metalstrips, defective welds in the glow switch assembly, and theintroduction of deleterious material into the glow switch.

A further object is an improved method of treatment of the bi-metalstrip comprising complete Washing and drying prior to the cutting off,forming, and welding, of the oi-metal in glow switch assemblies.

An additional object is a bi-metal strip washer comprising a tank havinga constant how of water therethrough and housed in a dome-shapedcondensing hood, both tank and hood having slitted felt pads at each endthereof, a blower on top of the hood for condensing the steam within anddrying the emerging washed bi-metal strip, and means for heating thewater in said tank.

Other objects will appear to those skilled in the art to which itappertains as the description proceeds.

Referring to the drawing, in which like symbols of reference refer tosimilar parts throughout:

Fig. l is a side elevation partially in section of a bi-metal stripwasher embodying our invention.

Fig. 2 is a transverse sectional view of the tank and hood, on the lineIIII of Fig. l, in the direction of the arrows, showing one of the padsin the end portion of the tank.

In the drawing, the bi-metal strip washer of our invention is designatedgenerally cy the ref erence numeral It. It has a tank 52, suitablybox-like in shape, which is separated by a partition it into a dirtywash section it and a clean wash section it. These sections respectivelyhave downward depending lower portions it and l? in which are mountedthe water-heating means 58 and !9.

The tank is mounted within a dome-shaped condensing hood 2t. shown inthe drawing, slitted felt pads 22, 2-3, 2 3 and 25 are provided in theend walls of the tank and hood to hold the hot water around a bi metalstrip 23 passing through the tank E2 and retain the steam inside thesteam condensing hood. Suitable openings or slits are provided in thepartition 53 and the pads 22, 23, 24 and 2-5 to permit passage of thebi-metal strip 28 therethrough. These pads are held in place by suitablemeans such as screws 29. Water is continuously circulated desirably witha uniform rate of flow from an inlet 26 in the lower portion ll, throughthe sections i5 and M of the tank l2 in the order named, and dischargedirom an outlet connection 30 depending from section Hi. An overflow hole32 is provided in the first or dirty wash section M.

The water heating means it and [9 are suitable electric immersion-typeheaters, an example being Type 1213444, as manufactured by theWestinghouse Electric Corporation. The condensing hood as has a doublewalled roof defining an air-heating chamber 36. Mounted on the top ofthe hood 2%] is a suitable blower lit for directing air at roomtemperature into the chain ber 35 of the hood .29, thereby condensingsteam on the inner surface of the dome from whence it runs down thecurved sides of the hood to and into the tank overflow in the bottomportion of the hood. The blower air passing through the chamber 34 isheated by the condensing steam and directed by means of outlet pipes 38onto both sides of the emerging washed strip to dry it as the stripleaves the felt pad 22.

According to our invention, the bi-rnetal strip 26 is unwound from areel (not shown) and into the slit through the felt pads 25, 24 at oneend of the washer it, into the dirty wash section M, through the slit inthe partition it, into the clean wash section E5, and thencesuccessively through the pads 23 and from whence it emerges clean and isdried by the hot air from the outlets The washed bi-inetal then proceedsto a welding machine (not shown) where it is out off to size, formedinto the desired configuration and welded into position in glow switchassemblies.

It will be seen from the foregoing description that our invention hasprovided a bienetal strip washer it and an improved method of preparingbi-metal strip for assembly in glow switches. The washer Hi consists ofa tank having a constant flow of heated water therethrough, and mountedwithin a dome-shaped condensin hood is, slitted felt pads 22, 23, 2 5and 25, at the ends of the tank l2 and hood 28, a blower 36 mounted. onthe hood for condensing the steam therein and drying the washedbi-metal, and a pair of immersion heaters i8 and it for heating thecirculating water to a desired temperature. The rate of water now ishigh enough so that the oi-metal strip is properly cleaned, while lowenough so that the water is boiled during the operation.

Although a preferred embodiment of our invention has been described, itwill be understood that modifications can be made.

We claim:

1. In apparatus for washing and drying bimetal strips prior to cutting,forming, and welding for glow switch assemblies in combination, a tankfor holding wash water, means for heating the water, a double walledcondensing hood above said tank, a slitted feld pad in each end portionof the tank for maintaining the heated water level above the strip andmeans on the top for blowing air into the double walled hood to heatsaid air and to condense steam on the inner surface thereof and warmedair outlet means from hood for drying the emerging washed birnetalstrip.

2. In apparatus for washing and drying bimetal strips prior to cutting,forming, and welding for glow switch assemblies, in combination, a tankfor holding wash water, means for heating said water, a dome-shapedcondensing hood with a double walled roof over said and means forblowing air at room temperature between the double walls of said hood toheat said air and to condense steam on the inner surface thereof andwarmed air outlet means from said hood for drying the emerging washedbi-rnetal strip.

3. In apparatus for washing and drying bimetal strips prior to cutting,forming, and welding for glow switch assemblies, in combination, a tankfor holding wash water, means for heating said water, a dome-shapedcondensing hood with a double walled roof over said tank, a slitted feltpad in each end portion of the tank and hood for maintaining the heatedwater level above the strip and containing the steam inside the condensing hood and means for blowing air at room temperature between thedou 1e walls of said hood to heat said air and to condense steam on theinner surface thereof and warmed air outlet means from said hood fordrying the emerging washed bi-metal strip.

4. In apparatus for washing and drying bimetal strips prior to cutting,forming and weld ing for glow switch assemblies, in combination a tankfor holding water, a double-walled condensing hood above said tank, saidhood providing a chamber for heating air and co densing steam, a slittedfelt pad in each end portion of the tank and the hood for maintainingthe heater water level above the strip and for containing the steaminside the condensing hood, and a ..lower on the roof of said hood fordirecting air at room temperature into chamber to heat said air and tocondense the steam on the 1111 er surface of said hood and warm airoutlet means from said hood drying an emerging washed bi-nietal strip.

5. in apparatus for washing and drying bi metal strips prior to cutting,forming, and welding for glow switch assemblies, in combination, a tankfor holding water and divided into a clean wash and dirty washcompartment by a partition, a depending extension on each coinpartrnent,an immersion-type electric heater in each extension, inlet means in theclean wash compartment extension for introducing water under constantflow into the clean wash compartment and outlet means in said dirty washcompartment for withdrawing said water f1 dirty wash compartment, adouble-walled condensing hood above said tank, said hood providing achamber for heating air and co densing steam, a slitted felt pad in eachend portion of the tank and the hood for niaintai -ing the heated waterlevel above the strip and for containing the steam inside the condensinghood, a a blower on the roof of said hood for directing air at roomtemperature into said chamber to heat said air and to condense the steamon the inner surface of said hood and warm air outlet from said hood fordrying an emerging washed bimetal strip.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,204,168 Wood June 11, 1940 2,234,593 Perm et a1. Mar. 11,19%1 238M560 Ward Sept. 11, 1945 2,522,071 Tait Sept. 12, 1950

